Tube sizing broach



NW H3, 3.9425 J. Y. @mima TUBE SIZING BROCH Filed March 4, 1943 INVENTOR fob?? ).//aze/f mwwgw.

` ATTQRNEYS Patented Nov. 13, 1945 TUBE SIZING BROACIEI` John Y. Blank-Bedford, Ohio, assigner to Lempco Products, Inc., Bedford, Ohio, a corporation of Ohio Application March 4, 194s, sera1N0. 477,9ss l v 1 Claim.

This invention relates, as indicated, to a tube sizing breach and method of using the same.

It has heretofore been proposed to breach articles such as cast thick-walled phosphor-bronze bushings and the like by means of smooth-tooth breaches having teeth which are rounded at; the top instead of being finished to a cutting edge as in the ordinary type of breach. In breaching such articles, the design of the breach teeth is usually suchthat the metal in the sides of the hole is slightly compressed with perhaps a slight increase in the hardness of the metal, but no appreciable increase in the outer diameter of the work is effected. In other words, the wall thickness is usually such as to form a primary factor limiting the attainment of a desired flow of metal and a maximum increase in the hardness and smoothness of the breached wall of the article, and the design vof the breach is a secondary limiting factor in this respect.

I have discovered that I can attain a desired flow of the metal and a maximum increase in hardness and smoothness of the wall in a breach;- ing operation by decreasing the wall thickness of the article being breached, and by utilizing for the breaching operation a breaching tool or breach having an improved teeth design.

Another object of the invention is to provide a breach or breaches having novelv means for facilitating lubrication of the breach during the breaching operations.

A further object of the invention is to provide a novel method of making shells for munitionpurposes.

A still further object ef the invention is to provide a novel semi-finished product suitable for manufacture into shells for munition purposes.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawings and the following description setting forth in detail-certain means and one mode of carrying out the invention, such disclosed means and mode illustrating, however', but `one of various ways in which the principle of the invention may be used.

In said annexed drawing- Fig. 1 is a vertical longitudinal cross-sectional view showing the breaching of a seamless tube by means of the novel breaching tool of the present invention;

Fig. 2 is a top plan view of one of the breaches shown in Fig. 1;

Fig. 3 is a transverse cross-sectional view of the line 3 3 of 'the portion I, and a portion 3 ef stilll smaller diameter, and which is threaded to permit attachment of the breaching tool te a plunger or ram r 4 of a suitable press (not shown).

Mounted on the portion 2 of the arbor, between the portion I thereof and the plunger 4 is a multiplicity of breaches 5, these breaches having suitable keyways o, splined to the portion 2 of the arbor. Each breach is also provided with a second keyway 1,

diametrically opposite the keyway 6, the key-v ways 7, when aligned with each other, providing a vertical passageway for feeding Aa lubricant 'therethrough and to the radialV openings 8 in the breaches, which communicate with the keyways 'I as shown in Fig. 3.

Each of the breaches 5 has faces 9 and I which are flat, smooth, and parallel with each other, as well as perpendicular to the bore Il in the breach. Each breach, moreover, has a pair of axially-spaced teeth I2 and I3, the teeth I3 having a diameter A, which is slightly smaller -than the diameter B of the teeth I2. Each teeth "has a cross-sectional contour consisting of a Vportion X which is parallel to the axis ofthe breach, a portion Y in the form of an arc of relatively small radius, and a portion Z in the form of an arc of considerably larger radi-us than the are Y.

The portions Y of the teeth I2 connect the portions X thereof with the face 9 of the breach, while the portions Z of the teeth I3 connect the portions X thereof with the face Il) of the breach.

The portions Z of the teeth I2 and portions Y of 'the teeth I3 are joined by a reentrant arc C of relatively large radius, providing an annular space or recess I4, which serves a purpose to be presently described.

It will be understood that the successive breaches as seen in Fig. 1, have teeth of gradually increasing diameter, beginning with the lowermost breach and proceeding upwardly. In a typical breaching operation, involving the breaching of seamless tubes of a diameter suitable for whereby they may be manufacturing 4.2 inch shells, the dimensions, A and B, for the teeth of the successive breaches, will be approximately as follows:

Breach No.

The portions X of the firstA two breaches may, if desired, be knurled as shown in Fig. 1 to facilitate initiation of the breaching operation.

In the use. of the breaching tool, the,l seamless tube T which is to be breached, is mounted vertically on the bed L of a press, and is loosely or approximately centered with respect to the breaching tool by'means ofpins P;

The breaching tool is then pushed downwardly through the tube T, the several breaches of the tool acting in succession to enlarge the bore of the tube byA an operation which compressesvand smoothes the metal in the sides of the bore, resulting in a maximumV increase in the hardness of the metal, a smooth and highly burnished wall` surface and a general increase in the toughness and strength of the tube.

` These results are believed te be due, in part at least, to the fact that the tube or article which is being breached has a relatively-thin wall',` which permitsl the tube toV expand laterally to a very small degree, but suflicientlyto take up seme of the stresses created by the wave-like flowl ofthe metal which is set up by the teeth of the breach.

In other words, the teeth of the breaches force the metal of the tube'inwardly as indicated in a; few thousandths of an inch, the stresses` created by the wave-like flow ofv metal are taken up sufliciently to produce a bore of: considerable hardness, which presents a smooth highly; bur-L nishedsurface.`

The .design of the teeth of the breach` further facilitates the flow of the metal as well asthe production of the. desiredznishof the boreofsthev tube.' The portions Z of the teeth,A are, gently curved soy as to force the metal. inwardly veryy gradually and` smoothly. The portions X of. tlief teeth, are instrumental in producing aA desired smoothing effect en the metal', andthe portions Y are curved suniciently to relieve thea flowingY metal at these points. The annularrspa'ces M. are sufficiently large to readily accommodate move ment of the flowing metal and to hold a fairly large supply of the lubricant.

' During the breaching operation, a lubricant is admitted through the passageway formed of the keyways "l, and such lubricant finds its way through the radial openings 8, into the annular spaces I4 and to the internal surface of the tube, providing a film of lubricant between the tool andbore of the tubular article, which greatly facilitates the breaching operation.

After the breaching operation, the breaching tool is withdrawn from the tube, stripper fingers F- being employed to hold the tube during such withdrawal.

It mayv beapparent from the foregoing that a method has been, provided by which tubular a1'- ticles may be formed of considerable toughness and strength, and having bore, the walls of which arefrelatively hard and smooth.

The foregoing method is particularly adapted ferthe manufacture of shells for munition purposes. In such manufacture, a desired internall finish can be obtained, which is very'smoethand unlikely toresult in: injury to persons handling the shells. While a slight increase in the outer diameter'of such shells results from the breach'- ingl operations, this is not objectionable, since a finishing cut or cuts may be taken to reduce the external diameter to thesize necessary for leading, and. at the same time, a desired external? smoothness and concentricity obtained;

Instead of mountingv separate breaches onv an arbor,` as described,l a. single breach unit may-be employed` having teeth corresponding to theteeth ofthe separate breaches shown.

Other forms maybe employed embodying they features of my invention instead of the one here following claim or the equivalent of. such stated elements be employed, whether. produced by my preferred method or by others embodying. steps equivalent to those stated in. the following4 claim.

I therefore particularly point out and distinctly claimvas my invention:

A breach having faces which are parallel with each other and perpendicular to theaxis of the breach, and a pair of` axially-spaced teeth one of which is of slightly smaller diameter than the other, each tooth having a cross-sectional contour consisting of a portion which is parallel to the axis of the breach, a portion in the form of anarc of relatively small radius and a portion in the form of an arc of considerably larger radius than that of the first-named arcuate portion, the smaller arcuate portion of one tooth ing` joined. by a reentrant arcr of relatively largev radius, providing anv annular space between said teeth.

JOI-IN Y; BLAZEK-` 

